Apparatus for the application of a single strip tread to a carcass

ABSTRACT

An apparatus for applying an endless single strip tread to the carcass of a tire in either toroidal or flat built unshaped form. An uncured rubber strip of tread material is applied to the tire carcass in substantially parallel, spaces, spiral convolutions by moving a movable conveyor assembly and the supply source for the tread material in a direction parallel to the axis of the tire carcass itself. The movement is in one direction only during application of the strip, and a constant step-off of the strip as it is applied to the tire carcass is obtained by control means which permit the speed of transverse travel of the conveyor assembly and the rotational speed of the tire carcass to be controlled according to a predetermined formula so that the tread is applied to the tire in a single pass of the movable conveyor and tread stock supply source. The apparatus also includes means for returning the conveyor assembly to its starting position automatically following completion of application of the strip to the tire. The apparatus also includes provision of a hump stock let-off device which can be utilized when a &#34;valley&#34; type tread contour is required. A stitcher is also utilized to stitch down the tread stock during the time that the device moves relatively of the tire body, and finally the method and apparatus is utilizable with any conventional tire-building machine or recapping machine, since the method and apparatus disclosed herein is utilizable either in applying a tread to a new tire carcass or in retreading a used tire.

L. M.. SYMONS APPARATUS FOR THE APLLICATION 01 A SINGLE Sept. 24, 1974STRIP THEM) TO A CARCASS Original Filed Aug. 13, 1970 9 Sheets-Sheet 1'FIG./

TREAD TREAD FIG. 5

HUMP STRIPS L i l FIG. 2

FIG. 4

Sept. 24, 1974 v SYMQNS 3,837,967

APPARATUS FOR THE APPLICATION OF A SINGLE STRIP TREAD o A CARCASSOriginal Filed Aug. 13, 1970 .9 She ets-Shee t Sept. 24, 1974 L. M.s'YMoNs 3,337,967 APPARATUS FOR THE APILICATION OF A SINGLE STRIP TREADTO A CARCASS 1970 Original Filed Aug. 13,

9 Sheets-Sheet 6 Sept. 24, 1974 SYMQNS 3,837,967

APPARATUS FOR THE APPLICATION OF A SINGLE STRIP .TREA Original FiledAug. 13, 1970 D TO A CARCASS 9 shts-sheet 7 Sept. 24, SYMONS v APPARATUSFOR THE APILICATION OF A SINGLE STRIP TREAD TO A CARC-ASS Original FiledAug. 13, 1970 9 Sheets-Sheet 8 M'SYMONS HE- APtLICATlON OF A SINGLESTRIP TREAD TO A CARCASS Original Filed Aug. 13, 1970 Sept. 24, 1974 L.

APPARATUS FOR '1 9 Sheets-Sheet 9 United States Patent O 3,837,967APPARATUS FOR THE APPLICATION OF A SINGLE STRIP TREAD TO A CARCASSLester M. Symons, Southfield, Mich, assignor to Uniroyal, Inc., NewYork, N.Y.

Original application Aug. 13, 1970, Ser. No. 63,407, now abandoned.Divided and this application Oct. 19, 1972, Ser. No. 298,919

Int. Cl. B29l1 17/02, 17/08, 17/10 U.S. Cl. 156-405 4 Claims ABSTRACT OFTHE DISCLOSURE An apparatus for applying an endless single strip treadto the carcass of a tire in either toroidal or fiat built unshaped form.An uncured rubber strip of tread material is applied to the tire carcassin substantially parallel, spaced, spiral convolutions by moving amovable conveyor assembly and the supply source for the tread materialin a direction parallel to the axis of the tire carcass itself. Themovement is in one direction only during application of the strip, and aconstant step-off of the strip as it is applied to the tire carcass isobtained by control means which permit the speed of transverse travel ofthe conveyor assembly and the rotational speed of the tire carcass to becontrolled according to a predetermined formula so that the tread isapplied to the tire in a single pass of the movable conveyor and treadstock supply source. The apparatus also includes means for returning theconveyor assembly to its starting position automatically followingcompletion of application of the strip to the tire. The apparatus alsoincludes provision of a hump stock let-off device which can be utilizedwhen a valley type tread contour is required. A stitcher is alsoutilized to stitch down the tread stock during the time that the devicemoves relatively of the tire body, and finally the method and apparatusis utilizable with any conventional tire-building machine or recappingmachine, since the method and apparatus disclosed herein is utilizableeither in applying a tread to a new tire carcass or in retreading a usedtire.

RELATED APPLICATIONS This is a division of application Ser. No. 63,407,filed Aug. 13, 1970, which is now abandoned.

BACKGROUND OF THE INVENTION This invention relates in general to themanufacture of pneumatic tires, and more particularly to an apparatusfor applying an endless strip of elastomeric material onto a tirecarcass.

The conventional method of forming a tread is to extrude a solid stripof rubber to the desired cross-sectional configuration of the tread,following which the extrusion is cut to its proper length, stored, andeventually applied to the tire.

This conventional method has certain disadvantages, among which are theexpense of the extruding equipment; the difficulty of maintaining theexact cross-sectional contour during extrusion; the difficulty incontrolling both the cross-section and the length of the tread followingthe cutting operation to avoid shrinkage; the problem of cost and spacefor storage; the difiiculty in obtaining and maintaining a secure spliceat the ends of the tread; and finally the difficulty in holding closetolerances in the tread area.

The improved method and apparatus disclosed herein represents an attemptto either eliminate or drastically reduce the seriousness of theaforementioned ditficulties.

3,837,967 Patented Sept. 24, 1974 DESCRIPTION OF THE PRIOR ART Thefollowing prior art is known to applicant:

Darrow, US. Pat. 1,335,879 Hanson, U.S. Reissue Pat. 25,349 Holman, US.Pat. 3,177,918 Guichon et al., US. Pat. 3,268,380 Bailey et al., U.S.Pat. 3,270,107 Glasby et al., US. Pat. 3,330,186 Gallagher, US Pat.3,421,958 Weitzel, US. Pat. 3,422,874.

The above prior art shows a variety of methods of applying an endlessstrip of material to various surfaces. For example, both Holman US. Pat.3,177,918 and Hanson U.S. Reissue Pat. 25,349 disclose methods forbuilding a tread on a pneumatic tire by applying an endless strip ofrubber thereto.

These devices, while apparently being directed to achieving a somewhatsimilar end result to that of applicant, are believed to be somewhatless desirable because of their specific construction and operation.

Thus, for example, in Holman a retreading machine has been disclosedwhich operates by utilization of an oscillating sector gear, which movesthe stitching apparatus and the stock supply apparatus back and forth inan oscillating fashion. Holman accordingly does not achieve the constantstep-off achieved by applicant together with the ability to build thetread on the tire body in one pass in a uni-directional mode ofoperation with a constant step-off.

Hanson also differs from applicants structure in the method of controlwhich primarily contemplates the use of a template and stylus ratherthan a positive control device.

SUMMARY OF THE INVENTION The general object of the invention is toprovide a means for applying a single strip of tread stock to theperiphery of a tire carcass in a single pass across the surface of thetire, with a constant step-off as the strip is spirally Wound onto thecarcass.

A further object is to provide an improved apparatus for building atread which is both fast and economical and also provides improvedquality control.

These objects are accomplished by providing a main frame, upon which ismounted a supply source for the tread stock, and a movable conveyor,both of which are movable transversely of the frame.

A building drum of any of a number of conventional types is located atone end of the frame and, by means of unique control means, the speedwith which the movable conveyor and the supply source move across theframe is correlated to the rotational speed of the drum, whereby apredetermined number of layers with a fixed step-01f between them isdeposited on the drum in a spiral configuration to achieve apredetermined tread configuration.

Operation of the device is further enhanced by providing a stitchermechanism which moves with the supply source and the movable conveyor tostitch the strip down onto the tire carcass as it is wound thereon.

Accordingly, an apparatus for applying a single strip of rubber to atire carcass to form a tread becomes the principal object of thisinvention, with other objects thereof becoming more apparent upon areading of the follow ing brief specification considered and interpretedin view of the accompanying drawings.

Of the drawings:

FIG. 1 is a diagrammatic view of a laminate of layers of tread rubber inconstant stepped-oif relation in accordance with one phase of theinvention.

FIG. 2 is a diagrammatic view on a reduced scale showing the finalcontoured shape of the laminate of FIG. 1.

FIG. 3 is a view similar to FIG. 1 with the addition of a pair of fillerstrips intended to form a valley type tread in accordance with anotherphase of the invention.

FIG. 4 is a view similar to FIG. 2 showing the final contoured valleyshape of the FIG. 3 laminate.

FIG. 5 is a side elevational view of the improved apparatus for singlestrip tread winding, showing the stitcher applicator in broken lines inthe retracted position.

FIG. 6 is a sectional view taken on the lines 66 of FIG. 5 showing thefiller strip mechanism.

FIG. 7 is a plan view of the overall apparatus shown in FIG. 5 partiallybroken away and with part of the stitcher applicator and the fillerstrip mechanism removed for clarity.

FIG. 8 is an enlarged sectional view taken on the lines 8-8 of FIG. 7.

FIG. 9 is an enlarged sectional view taken on the lines 99 of FIG. 7.

FIG. 10 is an enlarged plan view of the traversing mechanism with theconveyor rolls removed for clarity.

FIG. 11 is an elementary schematic electrical diagram showing the meansfor controlling the sequence of operations of the strip-winding process.

FIG. 12 is a schematic pneumatic diagram showing the valving system forcontrolling the various devices during operation of the process.

FIG. 13 is a view taken along the lines 13 13 of FIG. 10.

FIG. 14 is a view taken along the lines 1414 of FIG. 5.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT The overall apparatus forpracticing the invention is best shown in FIGS. 5 and 7 of the drawingsand includes a main frame 10; a tread stock let-off mechanism 30 whichis mounted on one end of the main frame for move ment transverselythereof; a movable conveyor assembly 50 also mounted on the main framefor movement relatively thereof in unison with the tread stock let-offmeans 30; and a stitching means 70 which is also carried by the mainframe and moves in unison with the tread stock letoif and the movableconveyor 50. The overall device also includes a filler stock let-offmeans 90 carried by the main frame and a fixed or stationary conveyor110 associated therewith. Finally, the device includes a conventionalbuilding drum 130; control means 160 and 170; and a drive means 140which drives both the drum and the movable conveyor.

The individual sub-assemblies just referred to as well as their specificmechanisms and their specific interrelationships with each other will bedescribed separately and in detail below. It is, however, believedappropriate to briefly describe the overall operation of the device in abroad manner at this point. Accordingly then, the general operation ofthe device is as follows.

First, the ply stock or tire carcass is built up on the building drummeans 130 in conventional fashion. Following this, the tread stock 33 isunwound from the tread stock roll 32 of the tread stock let-off means30, threaded across the movable conveyor assembly 50 and down onto itsstarting point on the tire building mechanism 130.

The exact number of convolutions desired is computed by a method whichwill be subsequently described in detail, and the various adjustmentmeans associated with the movable conveyor assembly 50 will be set toprovide the desired relationship between the traverse of the tread stocklet-off 30, movable conveyor 50, and stitcher 70 with regard to theperipheral speed of the drum rotation so as to achieve the exact numberof convolutions and the precise amount of step-off desired to obtain thenecessary tread configuration.

Once the strip of tread stock 33 has been started on the tire, thestitching mechanism 70 is actuated and brought from the broken lineposition of FIG. 5 to the full line position thereof. Following this,the entire traversing mechanism is actuated and the device will moveacross the main frame 10, feeding the necessary number of convolutionsonto the drum and automatically stopping at the outward limit of itstravel which has been predetermined. After the strip material has beencut, the mechanism is returned to the start position automatically uponraising the stitching means to the full line position of FIG. 5.

Following this, the finished tire can be taken from the drum. When avalley-type tread is desired, such as shown in FIGS. 3 and 4 of thedrawings, the filler strip let-off mechanism is employed in conjunctionwith the fixed conveyor 110 to apply this filler stock to the tirecarcass before the tread stock is applied.

Accordingly then, the overall apparatus disclosed provides a device forapplying an endless uncured rubber strip to a tire carcass in spiralconvolutions with a predetermined step-oif on each convolution that isheld constant, with the entire tread being applied in a single passacross the surface of the tire.

While the sub-combinations and overall operation of the assembly havingbeen described in a general fashion, the following will be a detaileddescription of each subcombination and its relationship to the overallstructure.

THE MAIN FRAME 10 The main frame 10 consists of a pair of parallelspacedapart bottom support members 11 which are mounted on the factoryfloor in conventional fashion. The frame also includes parallelspaced-apart rear upright braces 13, 13 and forward upright braces 14,14. The frame 10 also includes spaced-apart top support rails 12, 12 soas to form a generally cube-like skeleton frame to support the remainingsub-assemblies of the overall combination. Conventional bracing means,such as 18, 19, and 20, are also employed for strength and rigidity,with bracing means 19 also supporting the stationary conveyor 110.

The main frame 10 also includes a series of opposed pillow blocks 21, 21on top rails 12, 12 which hold transverse rods 21a, 21a upon which themovable conveyor 50 and the tread stock applying apparatus 30 arejournaled to facilitate their transverse movement.

The main frame 10 also has associated therewith extensions 11a, 11a ofits bottom support members 11, 11 which project to the rear of the unitunderneath the tread stock let-off means 30. This extension includes apair of parallel bars secured to the floor and has a transverse plate 25spanning the distance therebetween for purposes which will be describedin greater detail below.

HUMP STRIP LET-OFF ASSEMBLY 90 Turning next then to FIGS. 5 and 6 for amore detailed description of the filler strip let-off, it will be notedfirst that the same is only used when a valley tread contour, such asshown in FIGS. 3 and 4, is desired.

The assembly, which is mounted either on the main frame 10 or directlyon the floor, includes a pair of axiallyspaced shells 91 and 92 adaptedto carry the filler stock rolls 93, 93 which are, in turn, carried byand project from the upright support 17. These shells are journaled onshaft 94 which is driven by a motor 180 and chain and sprocket means181, also carried on the upper end of the support 17, to drive theshells 91 and 92.

The filler stock material 95 which is in two strips is, of course,carried on the rolls 93, 93 together with a separating material 96, suchas polyethylene, in well known fashion.

Also carried on and projecting from the upright support 17 is a secondrotatable shaft 101 upon which are journaled shells 98 and 99 whichreceive take-up rolls 100, 100 to receive the separating material 96.This apparatus is, of course, mounted beneath the filler stock materialsupply means on support 17.

Rotatably mounted between the braces 20, 20 of the main frame 10 areconveyor rolls 22 and 23. A third conveyor roll 24 is also rotatablyjournaled between the braces 25, 25 of the main frame.

The filler strip stock 95 and the separating material 96 are firstdirected from the supply roll 93 over the roller 23. The separatingmaterial 96 is then directed under the roll 22 and onto the take-up roll100, while the filler stock material is directed through a festoon 97beneath a festoon roll 97a and up over the roll 24. In this way, sincethe take-up roll 100 is driven, there is virtually no tension on thefiller strip material 95 during unwinding, with the separating material96 bearing most of the tension.

The filler strip stock 95 is then directed over the first roll 103 whichis carried by the main frame 10, and onto the fixed conveyor 110 whichprojects from the front of the main frame 10. For convenience ofillustration in FIG. 5, only the first and last conveyor rolls 111, 111of conveyor 110 are illustrated, with it being understood that aconventional conveyor is contemplated.

The motor 180 and chain and sprocket means 181, which operate the fillerstrip let-off mechanism, are automatically stopped when the lowerfestoon roll 97a reaches its lowest desired position, at which time thelower limit switch 102 (see FIG. 6) is actuated.

It should be noted that both the shaft 94, which carries the stock rolls93, 93, and the shaft 101, which carries the take-up rolls 100, 100 aresplit into two parts so that each strip can, if desired for any reason,be threaded separately and then locked together by conventional clutchassemblies 104, 105 and 106, 107 or similar devices for simultaneousrotation.

Furthermore, a brake 107 is provided in conjunction with the shaft 94which carries rolls 93, 93 to prevent excessive unrolling of the stockwhen the motor 180 is deactuated.

Once the filler strip stock 95 has been threaded as above described, itis merely necessary to actuate the motor 180 and the drum assembly 130and apply the filler strips about the periphery of the tire. Once thedesired length has been applied, the stock can be severed, spliced, andthe remainder of the building operation can take place.

The chain and sprocket driving connection 181 between drive means 180and the shafts has not been described in detail since it is believedapparent that while a chain and sprocket drive is illustrated, othersuitable means can be devised.

It should be noted also, as above mentioned, that the mechanism justdescribed is only utilized when the valley type of tread shown in FIGS.3 and 4 is being built.

THE TREAD STOCK LET-OFF MEANS 30 Turning next then to FIGS. 5, 7, and 14for a detailed description of the tread stock let-off means 30, it willbe first noted that in the general unwinding or feeding operation, thismechanism operates quite similarly to that of the filler strip let-offmeans 90.

Accordingly, shells 34 and 35 are mounted on a shaft 36 which is, inturn, carried on the frame of the tread stock let-E device 31. Theseshells 34 and 35 receive the roll 32 which carries the tread stockmaterial 33 and alsoseparating material or liner 37.

The liner take-up roll 38 is carried on the tread stock let-off frame 31and is journaled on shells 39 and 40, which are carried on rotatableshaft 41, for rotational movement in response to motor 42 and chain andsprocket drive means 43, as will be explained more fully below.

Also journaled for rotational movement on the frame 31 of the treadstock let-off means 30 are a series of three conveyor rollers 44, 45,and 46. The tread stock 33 and the liner or separating material 37 isfirst pulled from the roll 32, passed over the roller 44, and then theseparating material or liner 37 is passed under roll 45 and onto thetake-up roll 38. The tread stock 33 is permitted to form a loop, andthen the leading edge thereof is passed over the roll 46 and onto themovable conveyor 50. In this manner, during unwinding, the principalpull or tension is taken by the liner 37, since the take-up roll 38 isdriven, thereby avoiding any distortion or stretching of the tread stockmaterial 33.

In order to ensure the proper rate of feed and also to alert theoperator when the roll 32 is empty, first and second photo-electric stopswitches 47 and 48 are provided with each switch having an associatedphoto-electric receiver. Thus, when the loop in the bottom of the treadstock 33 rises above the switch 48, the motor 42 and drive 43 areactivated, and an additional amount of tread stock can be run off thedrum 32. This action is similar to the common utilization of a festoonin conjunction with photo-electric cells.

Similarly, when the stock loop rises above the switch 47, the switch 47will deactivate the motor, thereby preventing further feed. Also, whenthe end of the roll is reached, the photo-electric switch 47 isactivated, thereby stopping the feed and indicating to the operator atthe opposite end of the machine that it is time to change rolls.

It should be noted that shaft 36 has clutch 36a associated therewith aswell as brake 36b, while shaft 41 also has a clutch 41a, with theoperation of these components being described more fully below.

Referring again to FIGS. 5 and 7, it will be noted that the frame 31 forthe tread stock let-off mechanism 30 is journaled on shaft 21a which iscarried by the main frame. The fact that the frame 31 is journaled onthis shaft permits it to move transversely of the main frame 10 inresponse to the drive means 150, which will be subsequently explained ingreater detail.

At this point it is sufficient to note that an adjustment member 49 isprovided on the main frame, and by means of turning the hand wheel 49a,the position of the tread stock let-off frame 31, with relation to themain frame and the movable conveyor 50, can be adjusted laterally bymeans of threaded shaft 49b. In this fashion preliminary alignment isachieved to compensate for various sizes of tires, with it beingunderstood that this alignment is a rough alignment and that additionalfine alignment means are provided.

Mounted on the bottom of frame 31 is a cam follower or roller 31a whichrides along plate 25 of extensions 11a, 11a of main frame 10 forimproved stability during the time the tread stock let-off means 30 ismoving transversely of the frame.

Finally and as noted earlier, a motor 41 is carried on the frame 31 ofthe tread stock let-off means and provides driving power for the roll 32and the roll 38 through chain and sprocket means 43, as best shown inFIG. 5, No detailed explanation of this structure has been set forthhere since a simple belt or chain-type drive is contemplated except tonote, as above, that clutch and brake assemblies 36a and 36b and 4111are provided in conjunction with shafts 36 and 41, respectively.

THE MOVABLE CONVEYOR ASSEMBLY 50 Turning next then to FIGS. 5, 7, 8, and10 for a detailed examination of the movable conveyor 50, it will benoted that the same is basically a roller type conveyor which includes aframe 51, one end thereof being attached to the frame 31 of the treadstock let-off means 30, while the other end is mounted directly on crossshafts 21a, 21a for transverse movement relatively of the main frame 10(see particularly FIG. 10).

This conveyor assembly 50 is generally rectangular in plan with aplurality of transverse rollers 52, 52 mounted for rotational movementbetween opposed elongate side frame members 53, 53 and transverse endmembers 54, 54.

Movement of the movable conveyor 50 is controlled by the drive means140, which will be explained in greater detail below.

It should also be noted at this point that the conveyor 50, in additionto the components already mentioned, does contain guide rails 55 and 56which serve to ensure alignment of the strip as it is passed across thetop of the roller. Generally, the guide rail 55 is fixed in position onthe conveyor, while the guide rail 56 is movable transversely of theconveyor 50 by means of two slot pins 57, 57 (see FIG. 7).

THE DRIVE AND CONTROL MEANS 140, 160, 170

Turning next then to the means for driving the movable conveyor 50 andthe tread stock supply means 30 transversely of the main frame 10,attention is first called to FIGS. 7 and 10. Referring particularly toFIG. 7, it will be noted that the drive means 140 are mounted on a frame141 and consist of the motor 142 with a clutch 144 and appropriate chaindrive connections 143 to the shaft 145. In the form of the inventionillustrated, this drive connection is in the form of a chain andsprocket.

The shaft 145 is journaled on the top of frame 141 in a pillow block 146and is connected to input shaft 147 by coupling 148. Shaft 147 is, inturn, carried on the top frame element 12 of the main frame and extendsbeneath the movable conveyor 50. The drive shaft or input shaft 147terminates in a right angle gear 149, which is attached to a lead screw150 and a lead nut 151. The lead screw 150 is mounted at its opposedends in bearing blocks 152, 152 which are, in turn, mounted on crosspieces 153, 153 which are secured to the main frame 10. (See FIG. 9.)

In operation, actuation of the motor 142 will drive the input shaft 147and turn the screw 150 by means of the right angle drive 149.

Projecting from the top of lead nut 151 is a roller 154 which isreceived in groove 155a of bar 155 which is pivotally connected to thenut by pivot pin 155b. The opposed end of the bar 155 rides in guidemember 156, which is mounted on the movable conveyor 50.

The angle of the rod 155 with relation to the guide 156 can be alteredby means of adjustment and control means 160 shown best in FIGS. 9 and10. These adjustment means consist of a threaded shaft 161 carried bypillow block 164 on the side of conveyor 50 and operated by a hand wheel161a on one end, and with the other end being pivotally connected to thebar 155 by swivel block 162. Turning the shaft 161 will change the angleof the bar 155 with respect to the longitudinal axis of the conveyor asshown in FIG. 7. In this way travel of the movable conveyor 50 will becontrolled. Stated otherwise, the control or adjustment means 160controls the speed of traverse of the movable components of the overallapparatus, and thus controls the number of wraps. This also controls thestep off distance which is intended to be uniform for each wrap. Itshould be noted here that the guide means 156 and the angle bar 155 donot move relatively of each other during operation and that the bar isset, in FIG. 7, at its maximum helix angle which would result in thegreatest step-off and thus in a fast traverse.

Adjustment means 160 also includes a second bar or shaft 163 whichcarries degree indicia (not shown) on its surface so that the precisedegree of adjustment of the bar 155 can be ascertained.

A still further adjustment means 170 is provided on the main frame 10,with this means consisting again of a threaded shaft 171 mounted onbracket 171a and a control hand wheel 172. The end of the shaft 171 thatis opposed to the hand Wheel 172 is mounted in a block 173 so that theprecise starting point for the operation can be controlled by simplyturning the handle 172, which moves the entire mechanism relatively ofthe main frame.

Adjustment means 170 also includes a linear reading bar 174 mounted inoverlying relationship to shaft 171 8 to enable measurement of themovement caused by turning handle 172.

In operation, actuation of the motor 142 will, of course, cause theinput shaft 147 to rotate and, by virtue of the right angle gear 149,rotation will be transmitted to the lead screw 150, and the nut 151 willbe driven along the screw. Since roller 154 is received in the groove155a of the bar 155, this roller will be driven along the groove,thereby driving the conveyor 50 across the main frame 10. Thepredetermined angle of the bar 155 which, of course, as mentioned above,is controlled by adjustment means 160, will control the speed with whichthe conveyor moves.

THE STITCHING MEANS The stitching means 70, which are best shown inFIGS. 5 and 7, include a frame 70a which is carried on the end ofmovable conveyor 50 for movement therewith transversely of main frame10. Arm 74 is pivotally mounted at one end on roller 74a of conveyor 50and has its opposed end pivotally secured to a first piston 73 at 73a.

An A-frame 76 projects from the top of conveyor 50 and carries secondpiston which has the end of its rod 75a pivoted to arm 74 intermediateits ends at 75b. Similarly, the rod 73b of first piston 73 is pivoted toa forwardly projecting portion of arms 77, 77 which are also journaledon roller 74a.

Referring to FIG. 5 it will be seen that when pistons 73 and 75 areextended to the full line position, the bladder 71 which rotates betweenarms 77, 77 will be in stitching contact with the strip 33. When thepistons retract, the entire assembly is pulled up to the broken lineposition for rethreading or any other operation requiring access to thefront of the unit.

THE DRUM The building machine 130 can be any one of several commerciallyavailable models and will only be described in general terms. Thus, thecollapsible drum 132 is mounted on a support 131 and is positioned atthe right end of the unit as shown in FIG. 5 and is con nected to motor142 by chain drive 133 in known fashion.

OPERATION OF THE IMPROVED APPARATUS In order to operate this apparatusto achieve a predetermined size and shape or tread profile, the settingsfor the machine must first be computed by certain calculations.

Thus, and assuming that a tire is to be strip Wound to achieve a fiatprofile in the center region, and assuming again that the tread is to becalculated for a 12.00-24 tire, computations can be made in any one ofthree manners. First, and assuming that the operator has only a stripwith a fixed dimension of 4 inches by .150 inches available, thecomputation would be as follows:

Strip width 4 Number of layers 6.25

Step-off Tread thickness 30/32 Number of layers Strip thickness 5/32 6Therefore:

Number of layers 1 6- 1 Therefore: Stripwidth=Slope+Step-ofi=4%-|-.85t=5.1 1n.

The above method produces a perfect tread.

There is a third modified method which can be used when the stripthickness will vary, and this will be cheaper in the long run since thenecessity of producing and storing a wide variety of strip thicknesseswill be eliminated.

If we assume any given strip thickness, such as .140, then:

Tread thickness 6.7

Number of layers =m (It is, of course, impossible to have a fractionalnumber of layers, and the above figure is an approximation.)

Width of slope 4% Step-of; Number of layers 1 T 6.7 1

Width of strip=Width of slope+Step-ofi?=4%+.75=5.0

p Slope width 6 Number of layers- 1 9 -1 It then becomes possible todetermine the Width of the strip required, which in this example isequal to the slope width plus the step-off or 6.75 inches.

Since the number of convolutions will be equal to the crown plus theslope divided by the step-off, and assuming that in addition to theslope the total tread width requires an additional 17 inches in thecrown area, then by dividing 17 plus 6 by .75, the result is 30.6 orapproximately 31 convolutions.

Accordingly, and as will be seen from FIGS. 1 and 3 of the drawings inwinding this particular tread, the slope is formed from the first wrapto the ninth wrap, while from the ninth wrap to the last wrap thethickness re mains constant, and from the twenty-seventh wrap to thelast wrap the opposite slope is formed.

By mathematical calculations, which do not necassarily form a part ofthis invention, for any given width and thickness of strip and any givenspecification for the finished tread, it is simply necessary to adjustthe hand wheel 161a of the adjustment means 160 to change the angle ofthe bar 157. This controls both the step-oif and the speed of traverse,thereby controlling the wrapping of the tread so that the ultimate treadmeets the predetermined specifications.

Assuming then that the calculations have been made, and it is to beunderstood, of course, that these could be predetermined so that with agiven strip width and thickness and a given tread specification, theoperator can merely turn the hand wheel 161a and read on the bar 163 theappropriate reading. Then, and assuming that the control handle 172 hasbeen turned to achieve the proper starting point with regard to thetire, the operator is ready to begin.

CONTROL SEQUENCE Assuming that the machine is loaded and threaded asshown in FIG. 5, and that the stitcher is in the up or broken lineposition of FIG. 5, the leading end of the strip 33 can be put incontact with the tire carcass on the building drum. The main powerswitch will be closed to motor 180, 42, and 142, which are the fillerstock motor, the tread stock motor, and the main drive motor,respectively. The push button 300 is then actuated to furnish power to asignal light 301 and to energize the control relay 302, which will closethe normally open contacts 302a, 302b, and 3020. Contacts 302a and 302bfurnish power to the filler strip let-off device, the photoswitch lightsources and the photo-electric switches 47- and 48 for the upper andlower control of the tread strip let-off device 30.

Considering again then the light source 48, which is located at thebottom of the strip stock loop (see FIG. 5), the relay to motor 42 isenergized when the stock raises to the position above the photo-electricsvw'tch. Similarly, photo-electric switch 47, which includes a lightsource, is located near the top of the loop and serves to de-energizethe relay to motor 42 when the last of the stock has been used from thetread stock roll 32.

Closing of normally open contacts 302a and 3021) by operation of thepush button 300 also furnishes power to the controls for the stitchingdevice, the transverse motion of the movable conveyor 50, and rotationof the building drum.

When the tread strip is properly threaded, the lower photo-electricswitch 48 is de-energized, providing of course that the loop is belowthe light source. The upper photo cell 47 is also de-energized at thistime. Upon starting the device, the normally open push button 303 closesits contacts to energize solenoid 304a of the valve 304 which actuatesthe rod in the second cylinder 73 outwardly. Simultaneously contacts303a are open which deenergizes solenoid 304b.

Also with the arm 74 of the stitcher 70 in the up position, limit switch305 will be closed and actuated. Upon closing of switch 305, relay 307is also energized in order to close normally open contracts 307a andinterlock on the control panel (not shown).

Assuming that selector switch 306 is in the down position, its contactsare closed, and contact 30611 remains open. Since the selector switchcontacts are closed, normally closed contacts 308a will energizesolenoid 309a of the valve 309 to actuate the rod of the cylinder 73,thereby pressing the pneumatic stitching device 70 and the roll 71thereof into engagement with the strip 33, which has been previouslyplaced on the drum 132 in starting position.

Either prior to the actuation of push button 303 or following theabove-outlined control steps with selector switch 311 in the jogposition, selector switch 310 would normally be turned to the automaticposition, thereby closing contacts 310a and 310s and simultaneouslyopening contacts 31% and 310d, thereby energizing the relay to motorthrough closed contacts 310a. Closed contact 310c puts the automaticcontrol of the clutch 41a, which is associated with the rewind roll 38,on the normally open contact 312 of the lower photo-electric switch 48which activates the drive mechanism for the rewind roll when the lowerloop of the strip material 33 raises above the normal position. Asmentioned before, when the loop does raise above normal, the contacts312 of the switch 48 close, thereby energizing solenoid 313a of valve313 to engage the pneumatic clutch and drive the wind-up roll 38 so thatboth liner and strip stock material come from the roll 32simultaneously.

Simultaneously with closing of the contacts 312 by movement of the loopabove the normal position, contacts 314 open, but solenoid 313k remainsenergized to release the pneumatic brake 3612 on the stock roll 32. Theactions which result from the operation of solenoid 313a and 313b areintermittent due to the lower photoelectric switch 48, which alternatesthe simultaneous opening and closing of contacts 312 and 314 dependingupon the position and location of the strip 33.

In the event that a strip size change is required, such as when the rollis not completely used up and a change in tire size or treadspecification occurs, it is necessary to rewind the unused portion ofthe strip 33 onto the drum 32. At this point it would be necessary toturn selector switch 310 to the hand position so that contacts 310a and3100 will remain open, while contacts 31% and 310d are closed.

The rewind operation can be performed by turning selector switch 311 tothe rewind position which will then disengage the clutch on the rewindroll 38 and also the brake on the stock roll 32, so that the rewind canbe accomplished by motor 42. Push button 315 provides a safety stop tosolenoid 313a and solenoid 31312. A further safety stop is provided by amechanical detent stop 316, and its associated contacts 316a, 316b, and316a, which will stop the entire device including the tread stockletolf, the traverse and the gear motor. This controls the outer limitof travel of conveyorassembly 50. Once this button has been pushed,selector switch 316 must then be reset before reusing the traverse startbutton 317. At this point, and assuming again that the stock has beenthreaded and the control procedures outlined to this point have beenfollowed, the machine is then ready for operation.

Accordingly, push button 317 is actuated which energizes a time delayrelay 318 and the forward relay 319 for the motor 142 through thenormally closed contacts between the power sources. Energizing the motorforward relay 319 closes holding contacts 319a around push button 317and energizes the time delay relay 318 which closes contacts 318a toenergize a torque relay 320 which will control the initial slow startingspeed of the motor 142 during the time for which the delay has been set.

Because the motor 142 drives both the building drum and the transversemovement of the movable conveyor 50, the winding of the strip 33 ontothe tire carcass is accomplished and controlled by the traversingmovement.

At the end of the predetermined traversing movement. limit switch 321 isclosed and limit switch 321a is open. Upon actuation of these switchesrelay 308 is energized, opening the normally closed contacts 308a and308b. Open contact 308 de-energizes the relay 319, thereby stopping themotor 142, and the opening of contact 308a energizes the solenoid 309aof valve 309 which operates the cylinder 73 of the stitching mechanism70.

Simultaneously with the aforementioned energizing of contact 308 bylimit switch 321, solenoid 30912 is energized to reverse the action ofthe cylinder 73 which will raise the stitching roll 71 out of engagementwith the completed tire carcass on the drum 132.

Push button 322 is then actuated, thereby opening contact 322a tode-energize the solenoid 304a and close contacts 322b thereby energizingsolenoid 3041) to reverse the direction of the cylinders 75 and 73,thereby elevating the stitcher applicator to the starting position. Withthe upward movement of the arm 74, limit switch 79 is openedde-energizing contact 307 and opening contacts 307a, therebyde-energizing solenoid 323 which releases the drum drive forward clutch.Furthermore, when the arm 74 is raised to the upper or start position,limit switch 78 closes, thereby energizing motor reverse contact 325 toopen the contacts 325a to reverse the motor 142 whi h returns themovable conveyor 50 to its starting position, completing the cycle andplacing the device in position for a new cycle.

When a valley-type tread is required, such as shown in FIGS. 3 and 4 ofthe drawings, selector switch 326 is turned to the automatic positionfollowing energizing of contact relay 302 by push button 300. With theselector switch 326 in the automatic position, contacts 326a and 3260close, while simultaneously contacts 326b and 326d are open. Closedcontact 326a energizes contact relay 327 to operate the motor 180, whileclosed contact 326a energizes solenoid 328a of the valve 328 to engagethe clutch 107 on the wind-up roll 100. If the festoon 97 of the fillerstock material is at the bottom, the limit switch 102 is opened and therelay 327 is de-energized to stop the motor 180. When it is necessary tojog after threading the filler stock or rewind when required, selectorswitch 326 is put in the hand position, following which push button 330can be used to intermittently engage the solenoid 328a or, in the caseof the rewind, push button 331 can be held open to simultaneouslydeenergize solenoid 328a and energize solenoid 328b to engage the clutch105 on the stock roll 93.

To apply the filler strips 95 to the carcass on the drum 132, theoperator simply takes the leading ends from the conveyor and attachesthem to the tacky surface of the carcass. He then actuates the drum onerevolution, following which, of course, the strips are cut to properlength and the ends are spliced together. The controls mentioned aboveeffectively prevent any overrun or tearing of the filler stock 95.

It has accordingly been shown how a new fast and economic tire buildingmethod and apparatus has been produced in that a tread can be simply andquickly wound onto a tire in a single pass of the conveyor along theaxis of the tire, with the resulting tread being capable of beingproduced within extremely close tolerances so that a greatly improvedfinal result is achieved.

It has been shown by the foregoing how many of the difficulties commonlyencountered with regard to conventional tread manufacture, such asshrinkage, storage, poor splices. etc. have been eliminated.

It should be kept in mind throughout that the invention is not intendedto be limited in any way to new tires but can be used for retreadingpurposes as well. Furthermore, the actual drum unit can be any one ofseveral conventional tire building drums.

While a full and complete description of the invention has been setforth in accordance with the dictates of the patent statutes,modifications may be resorted to without departing from the spirithereof or the scope of the appended claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. An apparatus for building a tread on a tire carcass comprising meansfor applying axially spaced strips of filler material to the peripheryof the carcass;

means for applying the leading end of a strip of tread stock ofpredetermined dimensions to the surface of the carcass;

means for rotating the carcass at a fixed speed;

means for continuously traversing the tread stock strip axially of thecarcass with a constant step-off in only one direction continuouslyduring carcass rotation, and over the filler material;

whereby a spiral winding of a predetermined number of layers of thetread stock strip is applied to form a tread of predeterminedconfiguration in a single traverse across the periphery of the carcass.

2. The 'aparatus of Claim 1 further characterized by the presence of (A)means for stitching said tread stock while the same is being applied tosaid tire carcass.

13 3. The apparatus of Claim 1 further characterized by the presence of(A) means for aligning said tread stock with respect to said tirecarcass. 4. The apparatus of Claim 1 further characterized by thepresence of (A) stitching means (1) carried by said tread stock meansfor movement therewith (2) and being movable into and out of stitchingcon-tact with said tread stock.

References Cited UNITED STATES PATENTS Re. 25,349 3/ 1963 Hanson 156130-3,418,191 12/1968 Dieckmann, et a1. 156-130 2,365,341 12/ 1944 Haren, eta1. 1564'06 1,335,879 4/1920 Darrow 156--130 14 3,595,724 7/1971 Leblond156415 3,355,339 11/1967 Hineline 156-405 3,549,442 12/1970 Hineline156130' 3,497,408 2/1970 Hineline 156-130 3,748,203 7/1973 Greene 1561281,925,894 9/1933 Barder, et al 156-111 3,607,517 9/1971 Pelley, et a1.156-432 3,373,066 3/1968 Hindin 156128 FOREIGN PATENTS 528,335 110/1940Great Britain 156128 R DANIEL J. FYRITSCH, Primary Examiner I. E.KITILE, Assistant Examiner U.S. C1. X.R. 156-130, 397

